 Emmy here again and welcome to another episode of Cobb U. Now we've covered a lot of ground here at Cobb U and it's time to talk about how to get that power to the ground. Without a way to transfer power from our engine to our tires, we'd be going nowhere fast. So thankfully our drivetrain bridges that gap for us and allows us to put that power into action. Now what makes up a modern automotive drivetrain you say? Well I'm glad you asked. We've got transmission, differentials, trans-axles, normal axles, clutching, drive shafts and stuff that all that stuff comes in contact with like bushings and shifters. Now that's a lot of parts and there's a lot of interchangeable terms for these parts so for fun we've included an extra credit link for more information on that. Now that we've gotten the fun out of the way let's learn about how those components work together to make the magic happen. If we were to fully explore the world of drivetrain components this video would be very long so instead we're just gonna focus on the components themselves and how they work together. For today's example we'll be using an automatic transmission rear wheel drive front engine layout so we'll go over the basics of that system and learn how power gets transferred from the motor to the pavement. We start at the engine where the flywheel and clutch attach to the crankshaft. This completed assembly is mated to the front of the transmission. The transmission houses all your gears and transfers the power to the drive shaft via the rear of this housing. The drive shaft runs the length of the car to the rear differential. From there the differential transfers the power through the axles and finally turning your wheels to put the power on the ground. And that's the basics of a rear wheel drive car so now that we understand all of that let's take a look at some of the individual components of the drivetrain so we can learn a little more. First let's talk more about drive layouts. Now so far we've used rear wheel drive as an example but there's more than that. There's rear wheel drive, all wheel drive, and front wheel drive. Each is different and they have their own sets of pros and cons but they all do the job of getting the power to the ground. Now let's take a closer look at all three to see the differences. A rear wheel drive car sends power to the rear wheels. A front wheel drive car has power only going to the front wheels. An all wheel drive car sends power to all its wheels. We learned that in rear wheel drive cars the power travels from the engine to the transmission then through the drive shaft and last the differential distributes to the tires. Front wheel drive and all wheel drive cars are a little different though. They have some added components because of either their layout or distribution needs. Keep in mind that not all applications are identical and some will have more or less components but the basic concept will be the same. Front wheel drive engines generally sit sideways. The engine connects to the transmission which also contains a front differential driving a set of half shafts that spin your front wheels. All wheel drive engines sit either parallel or sideways. The distribution though is more complicated because there's many different ways of doing it. In one example like a Subaru the engine sits in the front and connects directly to the transmission. From there a center differential will distribute power between a front and rear differential each driving a set of half shafts to their respective wheels. On GTRs though the engine connects to a shaft that runs to the rear of the car where the transmission sits. From there power goes to the rear wheels through a rear differential and a second shaft connects from a transfer case to the front differential which turns the front wheels. And that's just the tip of the iceberg for drive layouts. We can make an entire episode on this subject alone so we'll just stop right there. Now let's talk about their pros and cons. Front wheel drive, pros, packaging. With the engine and transmission laying sideways the layout is compact and gives you more room in the cabin since there's no drive shaft running the length of the car or a rear differential. Cons, handling. The front wheels have to handle power, braking and turning. This is asking a lot and can lead to tire overload, excessive heat and torque steer. Front wheel drive also tends to understeer and lose some traction and heavy acceleration because weight gets transferred to the back. However, having the weight of the engine right on top of the drive wheels will actually increase traction and bad weather. Packaging. You gain more cabin room but it's a lot more cramped under the hood making it harder to work on. Rear wheel drive, pros. It's the fun one. Rear wheel drive cars have the most driver interaction and are very controllable. This is thanks to the better weight distribution of the drivetrain. Also, the front wheels now only have to steer and brake reducing the likelihood of understeering and torque steer. Cons, easiest to get in trouble. Also, tires can get expensive with all the burnouts you end up doing. Less cabin space. With drive shaft and rear differential, you lose the space you gain inside a front wheel drive car. All wheel drive, pros. Best traction. All wheel drive is ideal for all weather and terrain. Best for launching. Really good handling and easy to manage. Has the best of front wheel drive and rear wheel drive. Best cornering. Coming out of a corner with all four tires digging you out of the hole never felt so good. Cons, weight. With more parts comes more weight. And like rear wheel drive, less cabin space. Maintenance. With more parts, there's more chances of something going wrong. At the end of the day, each of these types gets the job done. What you should consider is how you're going to use your vehicle and that's going to help you determine the best style that suits you. Next up, transmissions. And there's a couple of types. Manual or standard transmissions which require you to shift from gear to gear using the clutch and shifter. Automatic transmissions which still uses several gears but does the shifting for you. Continuously variable transmissions or CVTs that are also automatic transmissions but function in a much different way using belts or chains and pulleys instead of gears. And dual clutch transmissions that are also technically manual transmissions but if desired can be set to auto and let the computer shift for you. Now let's talk a little more about differentials. This can be a pretty heavy topic so we're just going to go over the basics. A differential has a few basic jobs. To take the rotation of your shaft and convert it to spin the right way. To allow your wheels to spin at different speeds when turning. And to help control which wheel gets the power when needed. There are also different types of differentials. There are open and limited slip differentials. Open differentials provide the same rotational force to each of the wheels on the axle no matter which tire has more grip. Limited slip differentials on the other hand allow more torque to be delivered to the wheel with the most traction. Open differentials are more commonly found on your typical family sedan where you're not trying to go off-road or high performance driving just isn't a priority and you're just looking to get from point A to point B. Limited slip differentials are more commonly found on your sports car or high-powered luxury vehicle where handling and performance are a higher priority. If you want to learn more about differentials we have a really cool vintage video in the extra credit below. And now it's time for the pro tip of the day. You should always refer to your owner's manual or a good shop manual to make sure that you're changing your fluids at the proper intervals. But what happens when you change your gear oil from your differential and it's a glittery mess like some unicorn threw up in it. There's a lot of movement going on inside your differential with all that heat and friction that movement causes it's normal to see a small amount of light flaky specs when you change your gear oil. Most of the metal shavings should be caught by the magnetic drain plug. Now if your fluid is heavily contaminated with metal flakes like this or there's large metal chunks in the removed fluid you'll probably need to pop off the cover of your differential to check out what's going on inside. That's gonna do it for this episode. Be sure to subscribe to our YouTube channel so you can check out future episodes. I'm Emmy your host for Cobb U. Remember check out Cobbtuning.com for all your parts and tuning needs. Do you like the storage solutions featured in our studio? Then visit SonicToolsUSA.com to get more detailed product information.